Reynolds, who suffered a kidney injury in the Bedlam game against Oklahoma State, has been hospitalized for the last week.
Williams is battling a neck injury, while Ripkowski has a back injury.
"We've had some significant injuries over the last half of the season," Stoops said. "But this is an opportunity for other players. We're excited about our trip to Tempe and the opportunity we've got to reach 10 wins."
Both tore their ACLs earlier in the season.
OU will face Iowa in the Insight Bowl at 9 p.m. CT Dec. 30.